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如果我们把世界上主要玉米生产国产量提高的过程仔细分析一下,不难发现,当农业技术发展到一个比较高的水平时,尽管进一步地精耕细作,加大矿质营养的施用,但产量提高的幅度却很小。能不能把这种现象理解为作物的生产潜力发挥尽了,或者说达到了最高产量水平呢?在研究作物的光合作用和产量的关系时,发现有些作物的光能利用率还不到1%,甚至还不如它们的野生型,通过选种的手段,增加叶面积,改变生殖器官和营养器官的比例,能提高生产率。但还没有以改进光合作用器官作为育种的主要目标。因此,玉米的产量只能在光合潜力的允许范围内来提高,否则会发生同化产物积累与分配之间的不平衡,从而导致减产。植物生理学家估计,如果作物的光能利用率达到3—5%,加上现代化的农业技术和利用水、肥、光能及其它因子更好的品种,作物的产量可以
If we take a closer look at the process of increasing the output of the world’s major maize producing countries, it is not hard to see that while agricultural technology has reached a relatively high level, despite the further intensive and intensive efforts to increase the use of mineral nutrition, the rate of increase in output It is small. Could this phenomenon be understood as maximizing the productive potential of the crop, or at the highest level of yield? In studying the relationship between crop photosynthesis and yield, it was found that the utilization of light in some crops was less than 1% , Even not as good as their wild type, through the selection of means to increase leaf area, change the ratio of reproductive organs and vegetative organs, can improve productivity. However, the main goal of breeding has not been to improve photosynthetic organs. Therefore, the yield of maize can only be increased within the allowable range of photosynthetic potential, otherwise imbalance between the accumulation and distribution of assimilation products will occur, leading to the decrease of yield. Plant physiologists estimate that crop yields of up to 3-5% of the crop’s light use, combined with modern farming techniques and better varieties using water, fertilizer, light and other factors,